U.S. patent number 6,958,312 [Application Number 10/267,047] was granted by the patent office on 2005-10-25 for composition and method for removing copper-compatible resist.
This patent grant is currently assigned to LG.Philips LCD Co., Ltd.. Invention is credited to Gee-Sung Chae, Yong-Sup Hwang, Cyoo-Chul Jo, Byung-Uk Kim, Oh-Nam Kwon, Kyoung-Mook Lee, Sang-Dai Lee, Jong-Soon Yoo.
United States Patent |
6,958,312 |
Chae , et al. |
October 25, 2005 |
Composition and method for removing copper-compatible resist
Abstract
A composition for removing a copper-compatible resist includes
about 10% to about 30% by weight of an amine compound, about 10% to
about 80% by weight of a glycolether compound, and about 10% to
about 80% by weight of a polar solvent.
Inventors: |
Chae; Gee-Sung
(Incheongwangyeok-si, KR), Hwang; Yong-Sup
(Gyeonggi-do, KR), Jo; Cyoo-Chul (Gyeonggi-do,
KR), Kwon; Oh-Nam (Chungcheongnam-do, KR),
Lee; Kyoung-Mook (Seoul, KR), Kim; Byung-Uk
(Gyeonggi-do, KR), Lee; Sang-Dai (Gyeonggi-do,
KR), Yoo; Jong-Soon (Gyeonggi-do, KR) |
Assignee: |
LG.Philips LCD Co., Ltd.
(Seoul, KR)
|
Family
ID: |
27606975 |
Appl.
No.: |
10/267,047 |
Filed: |
October 9, 2002 |
Foreign Application Priority Data
|
|
|
|
|
Oct 10, 2001 [KR] |
|
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2001-62527 |
|
Current U.S.
Class: |
510/176; 134/2;
134/902; 510/201; 510/506; 510/505; 510/175 |
Current CPC
Class: |
G03F
7/425 (20130101); C11D 7/5013 (20130101); C11D
11/0047 (20130101); C11D 7/3281 (20130101); C11D
7/263 (20130101); Y10S 134/902 (20130101); C11D
7/3263 (20130101); C11D 7/3218 (20130101) |
Current International
Class: |
C11D
7/50 (20060101); G03F 7/42 (20060101); C11D
11/00 (20060101); C11D 7/22 (20060101); C11D
7/26 (20060101); C11D 7/32 (20060101); C11D
007/50 () |
Field of
Search: |
;510/176,175,212,499,407,401,202,505,506,201 ;430/331
;134/2,38,40,3,902 ;438/725 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Webb; Gregory
Attorney, Agent or Firm: McKenna Long & Aldridge LLP
Claims
What is claimed is:
1. A composition for removing a copper-compatible resist,
comprising: about 10% to about 30% by weight of an amine compound;
a glycolether compound; and a polar solvent, wherein the
glycolether compound has a molecular weight of less than about 150,
and the polar solvent includes at least one of
N-methyl-2-pyrrolidinone, N,N-dimethylacetamide,
N,N-dimethylformamide, and N,N-dimethylimidazole; and wherein at
least one of the glycolether compound and the polar solvent is
about 45% by weight.
2. The composition according to claim 1, wherein the amine compound
includes at least one of N-methylethanolamine, N-ethylethanolamine,
diethylethanolamine and dimethylethanolamine.
3. The composition according to claim 1, wherein the glycolether
compound includes at least one of ethyleneglycolethylether,
ethyleneglycolmethylether, ethyleneglycolbutylether,
diethyleneglycolbutylether, diethyleneglycolethylether,
diethyleneglycolmethylether and diethyleneglycolpropylether.
4. The composition according to claim 3, wherein the glycolether
compound has a boiling point more than about 180.degree.C.
5. The composition according to claim 1, wherein the amine compound
includes N-methylethanolamine, the glycolether compound includes at
least one of diethyleneglycolethylether and
diethyleneglycolpropylether, and the polar solvent includes
N-methyl-2-pyrrolidinone.
Description
The present invention claims the benefit of the Korean Patent
Application No. P2001-62527 filed in Korea on Oct. 10, 2001, which
is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a composition for removing copper
(Cu)-compatible resist, and more particularly, to a composition for
removing copper-compatible resist without corrosion of copper.
2. Discussion of the Related Art
In general, a low resistance copper line is commonly used as an
array line of an array substrate for a liquid crystal display (LCD)
device, or in a circuit line of a semiconductor device to prevent
resistance-capacitance (RC) delay. The copper line is commonly
formed using a photolithographic process incorporating fine pattern
technology. The photolithographic process is commonly used for
fabricating semiconductor devices such as large scale integrated
(LSI) circuits, very large scale integrated (VLSI) circuits, and
display devices including LCD and plasma panel display (PDP)
devices.
FIG. 1 is a perspective view of a liquid crystal display device
using a copper line according to the related art. In FIG. 1, a
liquid crystal display (LCD) device 11 includes an upper substrate
5, a lower substrate 10, and a liquid crystal material layer 9
interposed between the upper and lower substrates 5 and 10. The
upper substrate 5 includes a color filter layer 7, a black matrix
6, and a common electrode 18. The lower substrate 10 includes a
pixel electrodes 17 formed at pixel regions "P," and thin film
transistors (TFTs) "T" that function as switching devices. The TFTs
"T" are disposed in a matrix configuration and gate and data lines
14 and 22 are connected to each of the TFTs "T." The pixel regions
"P" are each defined by a crossing of the gate and data lines 14
and 22, and a transparent pixel electrode 17 is formed at each of
the pixel regions "P." The transparent pixel electrode 17 and the
common electrode 18 are made of a transparent conductive metal such
as indium-tin-oxide (ITO) and indium-zinc-oxide (IZO), and the LCD
device is driven by utilizing an electro-optical effect of the
liquid crystal material layer 9. Accordingly, the gate line 14
should be made of a low resistance material such as copper (Cu),
and should be formed using a photolithographic process
incorporating fine pattern technology.
FIGS. 2A to 2E are cross-sectional views of a photolithographic
process for forming a metal line according to the related art. In
FIG. 2A, a metal layer 32 is formed on a substrate 30 by deposition
of a metallic material. Next, a photoresist (PR) 34 of positive or
negative type is formed on the metal layer 32. In FIGS. 2A to 2E, a
positive type PR will be illustrated. Even though the PR 34 may be
formed on an entire or a predetermined region of the substrate 30,
the PR 34 is generally formed on the entire region of the substrate
30.
In FIG. 2B, a photo mask 36 is disposed over the PR 34 of the
substrate 30. Next, an exposure process is performed, wherein a
light "L" such as an ultra violet (UV) ray and an X ray is
irradiated onto the photo mask 36. The photo mask 36 includes a
transmitting portion "T" and a shielding portion "S," wherein the
light that passes through the transmitting portion "T" transforms
the PR 34. Accordingly, the PR 34 includes a first portion "A"
where a material property of the PR 34 is maintained and a second
portion "B" where a material property of the PR 34 is transformed.
Since the PR 34 is potentially patterned according to the photo
mask 36, this pattern of the PR 34 is referred to as a latent
image.
In FIG. 2C, the PR 34 (of FIG. 2B) having the latent image is
developed to form a resist pattern 35 that corresponds to the photo
mask 36 (of FIG. 2B). Specifically, the first portion "A" (of FIG.
2B) where the light "L" (of FIG. 2B) is not irradiated remains to
cover the metal layer 32 and the second portion (of FIG. 2B) where
the light "L" (of FIG. 2B) is irradiated is eliminated to expose
the metal layer 32.
In FIG. 2D, the metal layer 32 (of FIG. 2C) is etched using the
resist pattern 35 as an etching mask, whereby a metal line of a
specific shape is formed on the substrate 30.
In FIG. 2E, the resist pattern 35 (of FIG. 2D) is eliminated and
the metal line 38 of the specific shape is exposed.
However, the metal line formed of copper may be easily corroded by
conventional solvents that are used to remove the resist pattern
during the photolithographic process. Accordingly, solvent
compositions that include a corrosion inhibitor for preventing
corrosion of copper may be used, as demonstrated by U.S. Pat. Nos.
5,417,877 and 5,556,482, which are hereby incorporated by
reference. The corrosion inhibitors include mono-ethanol-amine
(MEA) as a preferred amine. In addition, a specific amount of
corrosion inhibitor is required so that a removing property of the
inhibitor is not degraded.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a composition for
removing a copper-compatible resist that substantially obviates one
or more of problems due to limitations and disadvantages of the
related art.
An object of the present invention is to provide an improved
composition for removing a copper-compatible resist.
Another object of the present invention is to provide a composition
for removing a copper-compatible resist without a corrosion of a
copper line when the copper line is substituted for an aluminum
line.
Additional features and advantages of the invention will be set
forth in the description which follows, and in part will be
apparent from the description, or may be learned by practice of the
invention. The objectives and other advantages of the invention
will be realized and attained by the structure particularly pointed
out in the written description and claims hereof as well as the
appended drawings.
To achieve these and other advantages and in accordance with the
purpose of the present invention, as embodied and broadly
described, a composition for removing a copper-compatible resist
includes about 10% to about 30% by weight of an amine compound,
about 10% to about 80% by weight of a glycolether compound, and
about 10% to about 80% by weight of a polar solvent.
In another aspect, a method for removing a copper-compatible resist
including combining about 10% to about 30% by weight of an amine
compound with about 10% to about 80% by weight of a glycolether
compound and about 10% to about 80% by weight of a polar
solvent.
It is to be understood that both the foregoing general description
and the following detailed description are exemplary and
explanatory and are intended to provide further explanation of the
invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are included to provide a further
understanding of the invention and are incorporated in and
constitute a part of this specification, illustrate embodiments of
the invention and together with the description serve to explain
the principle of the invention. In the drawings:
FIG. 1 is a perspective view of a liquid crystal display device
using a copper line according to the related art;
FIGS. 2A to 2E are cross-sectional views of a photolithographic
process for forming a metal line according to the related art;
FIG. 3 is a scanning electron microscope (SEM) image showing a
corrosion state of an exemplary copper line by a composition
including a monoethanolamine according to the present invention;
and
FIG. 4 is a scanning electron microscope (SEM) image showing a
corrosion state of another exemplary copper line by a composition
including a N-methylethanolamine according to the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to the preferred embodiments
of the present invention, examples of which are illustrated in the
accompanying drawings.
FIG. 3 is a scanning electron microscope (SEM) image showing a
corrosion state of an exemplary copper line by a composition
including a monoethanolamine according to the present invention,
and FIG. 4 is a scanning electron microscope (SEM) image showing a
corrosion state of another exemplary copper line by a composition
including a N-methylethanolamine according to the present
invention. In FIG. 3, a surface of the copper line may not be
smooth and may have a severely uneven. On the other hand, the
copper line of FIG. 4 may have a relatively smoother surface as
compared to the surface shown in FIG. 3. Accordingly, an amine and
a solvent which do not corrode the copper may be used, wherein a
resist may be removed without corrosion because an excess of a
corrosion inhibitor residue. Thus, the corrosion inhibitor may not
degrade the removal when the solvent is evaporated.
An exemplary composition for removing a copper-compatible resist
according to the present invention may include an amine compound, a
glycolether compound, and a polar solvent. The amine compound,
which is a strong alkali material, may penetrate into a polymer
matrix of a resist that may have been transformed or bridged
through a wet or dry etching process or by an ion implantation
process, for example. Accordingly, the amine compound may break an
attraction of internal molecules or may interrupt an interaction
between molecules. The amine compound may transform the resist into
a shapeless polymer cluster of a gel state by forming vacancies in
weak portions of the resist on the copper line, and the resist may
be removed. Accordingly, corrosion may be reduced when an amine
having alkyl radical attached to nitrogen (--N) is included by a
solvent. Moreover, a secondary amine compound may be better than a
tertiary amine compound in order to increase an activity of
unshared electron pair of nitrogen (--N--).
Table 1 shows exemplary basicity of the amine compound according to
the present invention.
TABLE 1 Classification Structure Ph 25% AQ sol'n monoethanolamine
primary ##STR1## 13.04 monoisopropanolamine primary ##STR2## 12.98
N-methylethanolamine secondary ##STR3## 13.11 dimethylethanolamine
tertiary ##STR4## 12.77 l diethanolamine tertiary ##STR5##
13.00
In general, corrosion of copper by the amine compound may be
independent of the basicity. The copper may become corroded only by
the amine, wherein two hydrogen atoms attached to nitrogen atoms of
alkanol (alkyl alcohol) are not substituted. Especially, the
corrosion may become severe when the amine ratio of the amine
compound is higher than about 30%. Furthermore, since the amine is
easily evaporated at temperatures above about 70.degree. C., the
amine ratio may not be controllable. Thus, the amine ratio may be
preferably within a range of about 10% to about 30% by weight.
Glycolether compounds remove copper-compatible resists by
dissolving resin of the resist. If a molecular weight of the
glycolether compound is more than about 150, dissolving activity is
reduced and solubility of the resist decreases. Accordingly, since
a secondary amine compound is used, dissolving activity of the
amine compound may also be reduced. Thus, the glycolether compound
may preferably have a molecular weight less than about 150.
Compounds without ether bonds, i.e., alkyleneglycol compounds, may
corrode a copper line resulting in pinholes on surfaces of the
copper line. Conversely, dissolving of amine compounds may be
obtained by using diethyleneglycolmethylether or
diethyleneglycolethylether, which have boiling points of more than
about 180.degree. C. and may be easily mixed with water.
Accordingly, even when the resist is removed during a high
temperature process, a composition ratio of the glycolether
compound may be constant because of the relatively high boiling
point of the glycolether compound. Thus, a removal rate of the
copper-compatible resist can be made constant throughout the
dissolving process. In addition, since the glycolether compound has
a boiling point of more than about 180.degree. C., a surface
tension between the resist and the copper line may be reduced,
thereby increasing resist removal efficiency. Moreover, since the
glycolether compound has a relatively low freezing point and a
relatively high ignition point, the glycolether compound is
relatively safe for storage.
Polar solvents for removing a copper-compatible resist may be
selected from the following: N-methyl-2-pyrrolidinone;
N,N-dimethylaceticamide; N,N-dimethylpormicamide; and
N,N-dimethylimidazole. Polar solvents dissolve polymer clusters of
gel state, which are transformed by an amine compound, into unit
molecules. Accordingly, the polar solvents prevent re-adhesion of
the resist during a cleaning process. Polar solvents such as
N-methyl-2-pyrrolidinone include the amine compound, which is a
functional group within the molecule, may help the amine compound
penetrate into the resist, thereby removing the resist. However,
N-methyl-2-pyrrolidinone has a low initial dissolution speed.
Accordingly, since N-methyl-2-pyrrolidinone has an tremendous
solubility to photosensitive materials, the dissolved
photosensitive material may not be educed. Conversely, polar
solvents such as N,N-dimethylaceticamide have a high initial
dissolution speed, whereby dissolved photosensitive materials may
be educed over a period of time and a possibility of re-adhesion
increases.
Table 2 shows exemplary corrosion of copper and a removal of resist
when an amine compound, a glycolether compound and a polar solvent
are individually used according to the present invention. In Table
2, two different types of samples are prepared. A first sample type
tests corrosion of copper by forming a copper layer about 2000
.ANG. in thickness upon a glass substrate, coating a resist on the
copper layer, and developing the resist. A second sample type tests
removal of resist by forming a chromium (Cr) layer upon a glass
substrate, coating a resist of the chromium layer, wet etching the
resist, and treating the resist with a dry etching gas. In
addition, in Table 2, monoethanolamine, N-methylethanolamine,
N-methyl-2-pyrrolidinone, N,N-dimethylaceticamide,
diethyleneglycolethylether, diethyleneglycolbutylether, and
tetraethyleneglycol are selected as solvent compounds.
TABLE 2 Corrosion of copper dipping 70.degree. C. Removal of resist
20 min. dipping 70.degree. C. 1 min. monoethanolamine entire
corrosion complete removal 10 N-ethylethanolamine entire corrosion
complete removal 10 N-methyl-2-pyrrolidinone no corrosion no
removal 0 N,N-dimethylaceticamide no corrosion partial removal 5
diethyleneglycolethylether no corrosion partial removal 5
diethyleneglycolbutylether no corrosion no removal 0
tetraethyleneglycol uniform pit partial removal 5
In Table 2, even though the amine compound such as monoethanolamine
and N-ethylethanolamine fully corrode the copper layer of the first
sample type, pit formation in the copper layer does not result.
Accordingly, the results shown in Table 2 may suggest a
controllability of corrosion of the copper layer. Conversely, even
though the glycolether compound such as tetraethyleneglycol does
not corrode the copper layer, corrosion control may be impossible
due to pit formation in the copper layer.
Table 3 shows exemplary corrosion of copper of an amine compound
according to the present invention.
TABLE 3 Corrosion of copper dipping 70.degree. C. 400 sec.
monoethanolamine 0 monoisopropanolamine 3 N-methylethanolamine 10
dimethylethanolamine 10 diethylethanolamine 10
In Table 3, the solvent compounds of Table 2 that corroded the
copper layer were added to a test solution that included an amine
compound, 45% by weight of a glycolether compound, and 45% by
weight of a polar solvent. Accordingly, different amine compounds
were selected including monoethanol, monoisoprpanolamine,
N-methylethanolamine, dimethylethanolamine and diethylethanolamine.
The test samples were dipped into the test solution at a
temperature of about 70.degree. C. for about 400 seconds. As shown
in Table 3, the test solution that included 45% by weight of a
glycolether compound, 45% by weight of a polar solvent, and one of
N-methylethanolamine, dimethylethanolamine and diethylethanolamine
never corrodes the Cu layer.
Table 4 shows ratios of a solvent composition for removing a
copper-compatible resist according to the present invention.
TABLE 4 Composition for removing resist Amine Glycolether Polar
compound compound solvent Additive kind wt % kind wt % kind wt %
kind wt % ratio 1 NMEA 10 DEGEE 80 NMP 10 ratio 2 NMEA 10 DEGEE 60
NMP 30 ratio 3 NMEA 10 DEGEE 40 NMP 50 ratio 4 NMEA 10 DEGEE 20 NMP
70 ratio 5 NMEA 20 DEGEE 70 NMP 10 ratio 6 NMEA 20 DEGPE 60 NMP 20
ratio 7 NMEA 30 DEGPE 50 NMP 20 ratio 8 NMEA 30 DEGPE 10 NMP 60
comparison ratio 1 MEA 10 DEGBE 60 DMAc 30 comparison ratio 2 MEA
10 DEGBE 45 NMP 45 BT 2 comparison ratio 3 NMEA 10 DEGEE 60 NMP 30
8-HQ 2 comparison ratio 4 NMEA 10 DEGEE 90 MEA: monoethanolamine
NMEA: N-methylethanolamine DEGEE: diethyleneglycolethylether DEGPE:
diethyleneglycolpropylether DEGBE: diethyleneglycolbutylether NMP:
N-methyl-2-pyrrolidinone DMPD: dimethyl-2-piperidone DMAc:
N,N-dimethylaceticamide BT: benzotriazole 8-HQ:
8-hydroxyquinoline
In Table 4, comparison ratios 1 and 2, monoethanolamine (MEA) was
used as the amine compound. In comparison ratio 2, benzotriazole
(BT) was added to the solvent composition as a corrosion inhibitor
of the copper layer. In comparison ratio 3, N-methylethanolamine
(NMEA) was used as the amine compound, and 8-hydroxyquinoline
(8-HQ) was added to the solvent solution as a corrosion inhibitor
of the copper layer.
Table 5 shows exemplary removal results of a resist when each
composition of Table 4 is used according to the present invention,
and Table 6 shows exemplary corrosion results of copper when each
composition of Table 4 is used according to the present invention.
Three different types of test samples were prepared. A first test
sample was about 1 cm.times.4 cm, and was prepared by etching an
active layer (a-Si:H/n+a-Si:H) and removing a resist on the active
layer. The second test sample was about 1 cm.times.4 cm, and was
prepared by forming a chromium (Cr) layer on a glass substrate, wet
etching, treating with a dry etching gas, and removing a resist on
the chromium layer. The third test sample was about 2 cm.times.4
cm, and was prepared by coating a positive photoresist
(DTFR-3650B:Dong-Jin semichem) on a glass, baking the resist at
about 170.degree. C. for about 5 minutes, and removing the
photoresist. Residual photoresist of the first and second test
samples was observed by a scanning electron microscope (SEM) and
residual resist of the third test sample was observed by a naked
eye. In Tables 5 and 6, a removal degree of the resist is expressed
by an integer within a range of 0 to 10, wherein integer 0
indicates no removal of the resist, and integer 10 indicates
complete removal of the resist.
TABLE 5 (1) (2) (3) dipping 200 sec. dipping 60 sec. dipping 50
sec. ratio 1 10 10 7 ratio 2 10 10 5 ratio 3 10 10 8 ratio 4 10 10
7 ratio 5 10 10 8 ratio 6 10 10 10 ratio 7 10 10 3 ratio 8 10 10 8
comparison ratio 1 5 2 0 comparison ratio 4 2 1 0 0: no removal 10:
complete removal
TABLE 6 (4) dipping 400 sec. ratio 1 10 ratio 2 10 ratio 3 10 ratio
4 10 ratio 5 10 ratio 6 10 ratio 7 10 ratio 8 10 comparison ratio 1
0 comparison ratio 2 0 comparison ratio 3 5(severe pit)
In Tables 5 and 6, the polar solvent corrodes even the active layer
in the case of comparison ratio 4. In the case of ratios 1 to 8 of
Table 5, the resist treated with the dry etching gas is completely
removed. Conversely, in the case of comparison ratio 4 of Table 5,
the resist is not removed. Accordingly, solubility of the hardened
resist is high in ratios 1 to 8, and solubility of the hardened
resist is low in comparison ratio 4.
In the case of comparison ratios 1 and 2 of Table 6, the
composition including monoethanolamine (MEA) severely corrodes the
copper layer. For the comparison ratio 2, even though benzotriazole
(BT) includes a complex with copper and an unshared electron pair
of nitrogen (N) is added as a corrosion inhibitor, BT is deficient
in preventing corrosion of the copper. For the comparison ratio 3,
even though 8-hydroxyquinoline (8-HQ) is added as a corrosion
inhibitor, a pit is generated in the copper layer because an
unshared electron pair of the nitrogen does not include a complex
with the copper.
Therefore, an exemplary composition for removing copper-compatible
resist may be suggested as follows according to the present
invention. The solvent composition may include about 10% to about
30% by weight of an amine compound, about 10% to about 80% by
weight of a glycolether compound, and about 10% to about 80% by
weight of a polar solvent. The amine compound may be selected from
a group that includes N-methylethanolime, N-ethylethanolamine,
diethylethanolamine and dimethylethanolamine. The glycolether
compound may be selected from a group that includes
ethyleneglycolethylether, ethyleneglycolmethylether,
ethyleneglycolbutylether, diethyleneglycolbutylether,
diethyleneglycolethylether, diethyleneglycolmethylether and
diethyleneglycolpropylether. The polar solvent may be selected from
a group that includes N-methyl-2-pyrrolidinone,
N,N-dimethylaceticamide, N,N-dimethylponnicamide and
N,N-dimethylimidazole.
In the present invention, it may be preferable to use
N-methylethanolamine as the amine compound,
diethyleneglycolethylether or diethyleneglycolpropylether as the
glycolether compound, and N-methyl-2-pyrrolidinone as the polar
solvent.
It will be apparent to those skilled in the art that various
modifications and variations can be made in the organic
electroluminescent display of the present invention without
departing from the spirit or scope of the invention. Thus, it is
intended that the present invention cover the modifications and
variations of this invention provided they come within the scope of
the appended claims and their equivalents.
* * * * *